Isotope Practice – Answer Key

Who Am I?

1.  Chlorine

2.  Manganese

3.  Krypton

4.  Boron

5.  Sulfur

6.  Iron

7.  Sodium

8.  Copper

9.  Neon

10.  Zirconium

11.  Mercury

12.  Potassium

13.  Calcium

14.  Radon

15.  Lithium

16.  Cobalt

17.  Barium

18.  Oxygen

19.  Helium

20.  Strontium

Which Atom Is Which?

A.  612C-

B.  1020Ne

C.  511B

D.  816O-

E.  24He

F.  11H+

G.  37Li+

H.  714N-

I.  49Be

I. Isotope Basics

1.  What is an isotope? Atoms of the same element with different mass numbers due to a difference in the number of neutrons

2.  What does the number next to isotopes signify? The mass number

3.  How can you tell isotopes apart? The number of neutrons

4.  For each of the following isotopes, write the number of protons, neutrons, and electrons.

Chromium-52 / Chromium-54 / 612C / 614C
#P / 24 / 24 / #P / 6 / 6
#N / 28 / 30 / #N / 6 / 8
#E / 24 / 24 / #E / 6 / 6
Nitrogen-15 / Nitrogen-20 / 1633S / 1632S
#P / 7 / 7 / #P / 16 / 16
#N / 8 / 13 / #N / 17 / 16
#E / 7 / 7 / #E / 16 / 16
Sodium-23 / Sodium-20 / 3479Se / 3478Se
#P / 11 / 11 / #P / 34 / 34
#N / 12 / 9 / #N / 45 / 44
#E / 11 / 11 / #E / 34 / 34
Iodine-108 / Iodine-114 / 2657Fe / 2660Fe
#P / 53 / 53 / #P / 26 / 26
#N / 55 / 61 / #N / 31 / 34
#E / 53 / 53 / #E / 26 / 26

Part II. Name the element/ion

5.  26 electrons, 29 neutrons, 26 protons Fe

6.  53 protons, 74 neutrons , 54 electrons I-

7.  20 protons, 18 electrons , 21 neutrons Ca2+

8.  30 neutrons, 28 protons, 28 electrons Ni

9.  4 protons, 8 neutrons, 2 electrons Be2+

10.  22 neutrons, 18 electrons, 18 protons Ar

11.  1 proton, 0 neutrons, 0 electrons H+

12.  13 protons, 13 neutrons, 10 electrons Al3+

13.  33 protons, 33 electrons, 42 neutrons As

14.  9 protons, 9 neutrons, 9 electrons F

Part II. Fill in the chart

Isotope / Isotopic Notation / A / Z / #P / #N / #E / Charge
Calcium-48 / 2048Ca / 48 / 20 / 20 / 28 / 20 / 0
Yttrium - 89 / 3989Y / 89 / 39 / 39 / 50 / 39 / 0
Uranium - 238 / 92238U3+ / 238 / 92 / 92 / 146 / 89 / +3
Neon - 21 / 1021Ne / 21 / 10 / 10 / 11 / 10 / 0
Nickel - 59 / 2859Ni2+ / 59 / 28 / 28 / 31 / 26 / +2
Francium - 218 / 87218Fr+ / 218 / 87 / 87 / 131 / 86 / +1
Plutonium - 238 / 94238Pu / 238 / 94 / 94 / 144 / 94 / 0
Copper - 65 / 2965Cu2+ / 65 / 29 / 29 / 36 / 27 / +2
Copper - 66 / 2966Cu / 66 / 29 / 29 / 37 / 29 / 0
Lead-207 / 82207Pb4+ / 207 / 82 / 82 / 125 / 78 / +4
Silver-109 / 47109Ag+ / 109 / 47 / 47 / 62 / 46 / +1
Europium-151 / 63151Eu / 151 / 63 / 63 / 88 / 63 / 0
Iodine – 127 / 53127I- / 127 / 53 / 53 / 74 / 54 / -1
Potassium - 39 / 1939K / 39 / 19 / 19 / 20 / 19 / 0
Fluorine – 19 / 919F- / 19 / 9 / 9 / 10 / 10 / -1